The present invention relates to a differential speed reduction apparatus and double-toothed gear for use therein and, more particularly, to a differential speed reduction apparatus employing a double-toothed gear having a uniquely generated tooth profile.
It is known in the art to employ a double-toothed gear in the differential speed reduction apparatus, wherein the gear wobbles in association with the rotation of an input shaft. For example, Japanese Patent Publication (unexamined) No. 54-120347 discloses a typical example of the differential speed reduction apparatus of such kind.
This prior art apparatus comprises a double-toothed gear capable of wobbling in association with the rotation of the input shaft, a stationary gear, and a movable gear connected to the output shaft. These gears are engaged with each other in a unique manner, but the unique engagement requires a specially generated tooth profiles. As a matter of fact, it is not easy to generate such unique gear profiles as to be required by the prior art. This is the reason why the prior art apparatus has not been put into practice.